Tank Base for Lego rubber tracks

Inspired by the Tiny Trak concept https://www.thingiverse.com/thing:2896083 I designed a chassis for the TowerPro MG 946R, a 360° continous rotating servo of standard size and the Lego rubber tracks with 34 tooth (680c01).

The servos ar monted wit M3x10 screws and the idler wheels get a M3x30 axis. The round servo horn is glued into the drive wheels. Dependig on the tolerance of your printer the idler wheels bore is tight by intention. But these Wheels have to spin free on the M3 screws. Mayb